1. Technical Field
The present invention relates to a substrate processing apparatus, and more particularly, to a gas distribution means including a plasma discharging part and a substrate treating apparatus including the gas distribution means.
2. Discussion of the Related Art
Generally, a thin film deposition process for depositing a thin film on a substrate and a photo-lithography process, which includes an etching process, for patterning the thin film are required to manufacture a semiconductor device, a display device and a thin solar cell. Among these processes, the thin film deposition process and the etching process are processed in a substrate treating apparatus having a vacuum condition. In the substrate treating apparatus, an activated gas or an ionized gas is provided onto the substrate through a gas distribution means to deposit the thin film on the substrate or etch the thin film from the substrate.
FIG. 1 is a cross-sectional view of the related art conventional substrate treating apparatus. The apparatus in FIG. 1 may be a plasma enhanced chemical vapor deposition apparatus.
Referring to FIG. 1, the substrate treating apparatus 10 includes a process chamber 12 for providing a reaction space, a susceptor 16 disposed in the process chamber 12 and a gas distribution means 18 for providing a process gas onto a substrate 14. The substrate 14 is disposed on the susceptor 16. A chamber lead 12a and a chamber body 12b constitute the process chamber 12.
The substrate treating apparatus 10 further includes an edge frame 20, a gas supplying pipe 22, a gate valve (not shown) and an exhaust port 24. The edge frame 20 is disposed at an inner side of the process chamber 12 to shield edges of the substrate 14. When the susceptor 16 is positioned at a process location, the edge frame 20 shields the edges of the substrate 14 such that a thin film is not deposited on the edges of the substrate 14. The gas supplying pipe 22 is disposed through the chamber lead 12a for supplying the process gas into the gas distribution means 20. The gate valve is a gate for the substrate 14. Remained gases in the process chamber 12 are exhausted through the exhaust port 24. In addition, a vacuum condition is controlled by the exhaust port 24. Although not shown, a vacuum pump may be connected to the exhaust port 24.
The chamber body 12b is combined to the chamber lead 12a with an O-ring (not shown). The gas distribution means 18 is electrically connected to the chamber lead 12a. A radio frequency (RF) power source 26 for providing a RF power is connected to the chamber lead 12a, and the susceptor 16 is grounded. A matcher 30 for impedance matching is installed between the chamber lead 12a and the RF power source 26. Accordingly, the chamber lead 12a and the susceptor 16 respectively function as an upper electrode and a lower electrode. When the process gas is provided into the reaction space, the process gas is activated or ionized by the upper and lower electrodes. A heater 26 is installed in the susceptor 14 to heat the substrate 14. A susceptor supporter 28 for moving upward and downward the susceptor 14 is disposed under the susceptor 14.
A gas diffusing space 32 is defined between the gas distribution means 18 and the chamber lead 12a. A baffle (not shown) is disposed in the gas diffusing space 32 such that the process gas is uniformly diffused. A plurality of gas injection holes 34 are formed at the gas distribution means 18 to provide the process gas toward the susceptor 16.
The thin film formed on the substrate 14 is required to have a uniform thickness and a uniform property. For example, the uniformity of the thin film is strongly affected by the uniformity of provided process gas. Accordingly, to uniformly provide the process gas, the plurality of gas injection holes 34 are formed at the gas distribution means 18.
However, there are problems in the related art substrate treating apparatus as followings. There is a deviation in a plasma concentration. Since the process gas is directly provided into a first region corresponding to each of the plurality of gas injection holes 34, a plasma concentration in a first region is greater than that in a second region between the injection holes 34. As a result, it is very difficult to obtain a uniform thin film because of the deviation of the plasma concentration.